Public Release: 

Research finds clue to why females live longer than males

Results could help researchers understand the mechanisms involved in aging

University of Exeter

A study from the University of Exeter has found that male flies die earlier than their female counterparts when forced to evolve with the pressures of mate competition and juvenile survival. The results could help researchers understand the mechanisms involved in ageing.

The research, published in the journal Functional Ecology, used populations of the fly Drosophila simulans that had evolved under different selection regimes. The study shows that mate competition (sexual selection), along with survival (natural selection), is tougher on male ageing than it is on females reducing their lifespan by about a third.

Some species, like the flies in this study, age quickly over a number of days while others - including some trees and whales - age slowly across centuries.

Professor David Hosken from Biosciences at the University of Exeter said: "We found dramatic differences in the effects of sexual and natural selection on male and female flies. These results could help explain the sex differences in lifespan seen in many species, including humans, and the diverse patterns of ageing we observe in nature."

The flies were subjected to elevated or relaxed sexual and natural selection and left to evolve in these conditions. To elevate sexual selection groups of males were housed with single females. A stressful temperature was used to elevate natural selection.

Males court females by singing, dancing and smelling good but their efforts come at considerable cost and this cost is amplified when they also have to cope with stressful temperatures.

The results of the study showed that under relaxed sexual and natural selection, male and female flies had very similar lifespans - around 35 days. However males that evolved under elevated sexual selection and elevated natural selection had a much shorter lifespan - just 24 days - and died seven days earlier than females under the same conditions.

Both sexual selection and natural selection were found to affect lifespan but their effects were greatest on males. The findings show that the sexes can respond differently to the same selection regimes.


The study was funded by Natural Environment Research Council, the Biotechnology and Biological Sciences Research Council and the Royal Society.

For further information:

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About the University of Exeter

The University of Exeter is a Russell Group university and in the top one percent of institutions globally. It combines world-class research with very high levels of student satisfaction. Exeter has over 19,000 students and is ranked 7th in The Times and The Sunday Times Good University Guide league table, 10th in The Complete University Guide and 12th in the Guardian University Guide 2014. In the 2008 Research Assessment Exercise (RAE) 90% of the University's research was rated as being at internationally recognised levels and 16 of its 31 subjects are ranked in the top 10, with 27 subjects ranked in the top 20. Exeter was The Sunday Times University of the Year 2012-13.

The University has four campuses. The Streatham and St Luke's campuses are in Exeter and there are two campuses in Cornwall, Penryn and Truro. The 2014-2015 academic year marks the 10-year anniversary of the two Cornwall campuses. In a pioneering arrangement in the UK, the Penryn Campus is owned and jointly managed with Falmouth University. At the campus, University of Exeter students can study programmes in the following areas: Animal Behaviour, Conservation Biology and Ecology, English, Environmental Science, Evolutionary Biology, Geography, Geology, History, Human Sciences, Mining and Minerals Engineering, Politics and International Relations, Renewable Energy and Zoology.

The University has invested strategically to deliver more than £350 million worth of new facilities across its campuses in the past few years; including landmark new student services centres - the Forum in Exeter and The Exchange at Penryn - together with world-class new facilities for Biosciences, the Business School and the Environment and Sustainability Institute. There are plans for another £330 million of investment between now and 2016.

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